Releasing collar



Mamch 10,- 1970 1E. BURNS 3,499,664

nmmsme COLLAR Filed July 29, 1968 2 Sheets-Sheet 1 Jhuen for 10007 Bur/4s T QW United States Patent 3,499,664 RELEASING COLLAR Erwin Burns, Los Angeles, Calif. Burns Tool Company, 8346 Salt Lake Ave., Bell, Calif. 90201) Filed July 29, 1968, Ser. No. 748,336

Int. Cl. F16] 35/00, 37/00, 55/00 US. Cl. 2852 8 Claims ABSTRACT OF THE DISCLOSURE A fluid conducting releasing collar for engagement in an elongate string of tubing engageable in a well structure and such that it will permit rotary drive of the tubing string, allow for lowering and raising of the tubing string when said tubing is subjected to tensile forces below a predetermined maximum force and is such that it separates when said string is subjected to tensile forces in excess of said predetermined maximum force, said collar comprising an elongate, tubular upper section fixed to a portion of the tubing string above the collar, an elongate tubular lower section fixed to the portion of the tubing string below the collar and having an upper portion slidably engaged in the upper section, circumferentially spaced flats about the upper end of the lower section and drive blocks carried by the upper section and engaging the flats to establish rotating driving engagement between the sections, an annular ring about the lower section adjacent the lower end of the upper section, circumferentially spaced registering openings in the ring and the upper section, shear pins in the openings, a removable retaining sleeve in the upper section normally overlying the openings and retaining the pins therein, and outer keeper sleeve carried by the upper section to normally overlie the openings and retain the pins therein and releasably maintaining the ring in fixed axial position adjacent the lower end of the upper section.

In the course of drilling and servicing oil wells, various and special oil tools are employed. The tools are normally engaged on or in strings of fluid conducting tubing and are lowered into the wells by means of the tubing strings and are operated by raising, lowering and/ or rotating the tubing strings and/or by means of fluid circulated downwardly through the tubing strings.

It is not infrequent that oil tools become stuck or hung up in wells and cannot be removed or pulled from the wells by means of the tubing strings with which they are related. In such cases, attempts to pull the tools by means of the tubing strings are made, until the tubing strings part or break, whereupon the tools and the portions of the tubing strings related thereto and left in the wells must be removed from the wells by diflicult, costly and time-consuming fishing operations.

The principal difiiculty or problem in fishing out tools and tubing lost or left in well structures, as a result of breaking of tubing strings in the manner set forth above, resides in the fact that it cannot be determined where the tubing string will separate or break. It is possible that it will separate or break immediately adjacent the tool which is stuck, in which case fishing the tool out of the well can be accomplished easily, rapidly and economically. On the other hand, and which is more frequently the case, the tubing strings separate and break a considerable distance above the tools, making it necessary to remove and fish out a considerable amount of tubing before the stuck tool is even reached. When a tubing string breaks or separates several hundreds of feet or more than 1,000 feet above a stuck tool, fishing or removing the tool and left-in tubing is a major and costly operation.

3,499,664 Patented Mar. 10, 1970 An object of my invention is to provide a releasing collar for engagement in a tubing string which is such that it will break or separate when subjected to predetermined tensile forces whereby it can, by placement of my new collar in a tubing string, be determined where the string will break or separate should the string and/or a tool carried by it become stuck in a well.

Another object of my invention is to provide a releasing collar of the character referred to which provides an uninterrupted flow passage for fluid conducted in a tubing string in which the collar is related.

It is a further object of this invention to provide a collar of the character referred to having releasing means comprising a plurality of pairs of aligned shear pin receiving openings and such that the number of shear pins employed can be advantageously varied to vary the breaking or separating forces required to separate or release the collar.

Yet another object of the present invention is to provide a releasing collar construction of the character referred to wherein the pairs of aligned shear pin receiving openings are clear through openings in their related parts and a construction wherein the said openings are closed by axially shifta'ble retaining and keeper sleeves whereby the pins in the openings can be easily and conveniently inserted and/or removed from the construction, thereby making assembly and servicing of the construction easy and simple.

Still another object of this invention is to provide a collar of the character referred to in which one of the shear pin receiving openings of each pair of said openings is provided in an annular, uninterrupted rotatable ring, which ring can be slidably moved into operating position and relative to other elements of the construction and is such that it can be advantageously releasably maintained in fixed axial position and for free rotation relative to related parts and/ or elements of the construction.

An object of the invention is to provide a collar of the character referred to having simple, easy-to-establish and service sealing means to prevent the escape of fluid flowing through the construction.

Another object of the invention is to provide a releasing means which is such that the shear pins are snug in their related openings and so that no slip or play occurs between the openings and the pins which would result in undesired, premature deformation and weakening of the pins.

Finally, it is an object of this invention to provide a releasing collar of the general character referred to which is simple, practical and rugged, a collar which is extremely easy and economical to manufacture, service and maintain, and a collar which is highly effective and dependable in operation. 7

The foregoing and other objects and features of my invention will be fully understood from the following detailed description of a typical preferred. form and application of my invention, throughout which description reference is made to the accompanying drawings, in which:

FIG. 1 is an elevational view of my new collar, show ing it arranged between a tubing string and a tool and showing the string and the tool arranged in a well;

FIG. 2 is a view similar to FIG. 1 showing the releasing collar separated;

FIG. 3 is a detailed, longitudinal, sectional view of my new collar taken substantially as indicated by line 3-3 onFIG. 1;

FIG. 4 is an exploded view of a portion of my new collar with parts and portions in section to better illustrate details of the construction;

FIG. 5 is a sectional view taken as indicated by line 5-5 on FIG. 3;

FIG. 6 is a sectional view taken as indicated by line 66 on FIG. 3; and

FIG. 7 is a sectional view taken as indicated by line 77 on FIG. 3.

For the purpose of illustrating one typical use of my new releasing collar, I have, in FIGS. 1 and 2 of the drawings, shown my collar arranged and/ or incorporated in a means provided for injecting steam into a well W for the purpose of heating the oil producing formation F and to thereby induce the free flow of oil therethrough. The oil well W is shown as including a bore in the earth and extending from the surface 11 of the earth, downwardly into the formation F. The bore 10 is provided with a suitable casing 12.

Extending longitudinally through the casing, from the top to the lower portion thereof, is an elongate string of tubing S made up of a plurality of stands or lengths of pipe screw threaded together in end-to-end relationship and downwardly through which steam is conducted.

Fixed to the lower end of the string S is the releasing collar A that I provide.

A fluid conducting packer construction P is fixed to and depends from the collar A and a tubular stinger T is fixed to and depends from the packer into the portion of the well bore below the casing and extending into the formation F.

The packer P has an expansible rubber packing member 10 to seal the annulus between the casing and the packer body 11 and to prevent steam introduced into the well from escaping back up through the annulus between the casing and the tubing string.

The packer P, in accordance with common practice, is further provided with hold-down slips 12, above the packing element, which slips are actuated into engagement with the casing and serve to prevent the packer construction and the tubing string from being urged upwardly and out of proper position in the well by the steam and/or by other fluid and/or gas pressures within the production formation.

- During the operation of injecting steam downwardly through the tubing string S, collar A, packer P, stinger T and into the formation F, the heat encountered at the packer vulcanizes the rubber packing element 10 to the casing.

When it is desired to pull the tubing string S, packer P and stinger T from the well, if the holding force afforded by the packer element exceeds the safe tensile limits of the: tubing string, the collar A breaks and separates, leaving only the lower portion of the collar A, the packer P and the stinger T in the well. None of the string is left in the well to be fished therefrom.

Another course of sticking the packer in the well and instead of or supplementing the holding action caused by vulcanizing the rubber packer element to the casing, is sticking of the hold-down slips in their out or actuated position.

With the collar separated and the tubing string S pulled from the well, a suitable go-devil can be run into the well to' release the slips and/or cut the packer element free, whereupon the structure left in the well can be suitably engaged and pulled from the well.

In the ordinary steam injecting means of the character referred to and which does not include the releasing collar A, the tubing string breaks and separates at its Weakest point intermediate its ends, when the packer becomes stuck, and it is necessary to cut up and fish out all the tubing left in the well before the packer can be freed and before the packer and stringer can be pulled from the well.

The releasing collar A that I provide includes an elon- 2 u u ar, flu d conduct g upp r e tion U. a e o gate, tubular, fluid conducting lower section L, drive means D establishing rotary driving engagement between the sections U and L and releasing means R releasably holding the sections U and L against relative axial shiftmg.

The lower section is an elongate unitary structure with a major, lower, outside, cylindrical surface 20, a minor, upper, outer cylindrical surface 21 (of less diametric extent than the surface 20) extending from the upper end of the section to the lower portion thereof and terminating at its lower end to define an upwardly disposed, annular stop shoulder 22, a central, longitudinal fluid passage 23 and an enlarged bore 24 entering its upper end and terminating in its central portion to define an upwardly disposed annular shoulder 25.

The upper end of the section L terminates at a flat annular top end and the lower end 26 is provided with an externally threaded, tapered pin 27 which establishes the male section of a tool joint to facilitate connecting the collar with related structure, such as the packer P.

In addition to the foregoing, the lower section L is provided with a plurality (three) of circumferentially spaced longitudinally extending flats 28 in the upper, minor, outer surface 21, which flats extend downwardly from the upper end 26 of the section, a limited distance, and form a portion of the drive means D, as will hereinafter be described.

The lower section L is further provided with a plurality of circumferentially spaced, radially inwardly and outwardly opening inner shear pin receiving openings 29 located a short distance above the shoulder 25 and forming a part of the means R and an annular, radially outwardly opening sealing ring grooves 30 in the surface 21, below the openings 29.

The upper section U is an elongate unitary structure with an upper, major, outside cylindrical surface 31, a lower, minor outside cylindrical surface 32, the upper end of which terminates to define an annular, downwardly disposed stop shoulder 33, a major, lower inside bore 34 equal in diameter With the upper, minor outside surface 21 of the lower section, entering the lower end of the section U and terminating in the upper portion thereof at an annular downwardly disposed stop shoulder 3-5, a minor bore 36 equal in diametric extent with the bore 24 in the lower section, and an internally threaded socket or box 37 entering the upper end of said section, which box establishes the female section of a tool joint to facilitate connecting the collar with a related structure, such as the lower' end of the tubing string S.

In addition to the foregoing, the section U is provided with a counterbore at and between the upper end of the bore 36 and the box 37, which counterbore establishes a socket 38 with an annular, upwardly disposed shoulderlike bottom 39.

The upper section is further provided with a plurality (three) of circumferentially spaced, longitudinally extending, radially inwardly and outwardly opening slotlike apertures 40 at the upper portion of the bore 34 and in which suitable drive blocks 41, with flat, radially inwardly disposed surfaces 42, are arranged and fixed, as by welding. The flat surfaces 42 of the blocks 41 are adapted to oppose and establish flat sliding engagement on the flats 28 on the lower section L, as clearly illustrated in FIGS. 3 and 5 of the drawings.

The block 41 and the flats 28 cooperate to define the drive means D and prevent relative rotation between the sections U and L when the construction is made up or assembled, but do not impede or interfere with relative axial movement of the sections U and L.

Finally, and in addition to the above, the section U terminates at a flat, annular, downwardly disposed bottom 44 and the lower end portion of the lower minor outer surface 32 is threaded as at 45.

When the structure is assembled, the upper portion of the lower section L i slidably ngaged in the upper sec;

tion U with the surfaces 21 and 34 in sliding engagement and with the upper end 26 of the lower section stopped against the shoulder 35 in the upper section and with the surfaces 42 of the blocks in sliding engagement on the flats 28.

The openings 29 in the lower section occur in spaced relationship below the lower end 44 of the section U.

The collar construction A next includes an annular ring 50 less in outside diameter than the minor diameter of the threads 45 on the upper section U and slidably engaged on the lower section about the upper, minor surface 21 thereof, below and stopped against the lower end 44 of the upper section U. The ring is an elongate, tubular part of limited axial extent and is provided with a plurality of circumferentially spaced, radially inwardly and outwardly opening outer shear pin receiving openings 51 which register with the inner shear pin receiving openings 29 in the upper section U.

An elongate, cylindrical, radially extending shear pin 55 is slidably engaged in and through each pair of registering inner and outer shear pin openings, as clearly shown in FIGS. 3 and 6 of the drawings.

With the above relationship of parts, it will be ap parent that the ring 50 is releasably fixed to the lower section U by the shear pins 55.

To prevent the shear pins 55 from shifting radially inwardly and becoming displaced from the inner openings 29, the construction is provided with an elongate, tubular retaining sleeve 60 equal in inside diameter with the passage 23 in the lower section and equal in outside diameter with the upper minor bore 36 in the upper section U. The sleeve 60 is provided with a radially outwardly projecting flange 61 at its upper end which seats in the socket 38 in the upper section U and depends from said socket through the bore 36 into the bore 24 to overlie the inner ends of the openings 29 and to stop at the stop shoulder 25, in the section L.

With the sleeve 60 that I provide, the openings 29 need not be blind openings and when it is desired or when it becomes necessary to remove and replace the shear pins 55 in the openings 29, the sleeve 60 can be removed so that the pins 55 or portions of the pins 25 in the openings 29 can be easily and conveniently urged radially inwardly and out of engagement in the openings 29.

Finally, to releasably maintain the ring 50 in fixed axial position relative to the upper section and to overlie the outer ends of the outer shear pin receiving openings and releasably maintain the shear pins engaged in the openings 51, I provide a keeper sleeve 70. The sleeve 70 is a unitary, elongate, cylindrical part having a cylindrical outer surface 71 equal in diametric extent with the upper outer surface 31 of the upper section U and a central bore 72 equal in diameter and slidably engaged about the upper outer surface 21 of the lower section L and flat, annular, upper and lower ends 73 and 74 opposing the stop shoulders 33 and 22 of the section U and L, as illustrated in the drawings.

The sleeve 70 is provided with an upwardly opening socket with a lower portion 72 corresponding in longitudinal extent and in diametric extent with the longitudinal extent and in diametric extent with the longitudinal and the outside diametric extent of the ring 50, a central, threaded portion 76 to engage the threads 45 of the section U and an upper portion 77 slidably receiving the portion of the lower minor outside surface 32 of the section U, above the threads 45.

The upper end 73 of the sleeve 70 normally engages and stops against the shoulder 33 and the lower end 74 thereof is spaced above the shoulders 22. The longitudinal extent of the sleeve 70 and the normal distance between the sleeve and the shoulder 22 is proportional so that when the sleeve is turned and unthreaded from engagement with the upper section U and is moved down into engagement with the shoulder 22 on the section L, the upper end of the sleeve occurs a suflicient distance below the inner shear pin receiving openings 29 in the section L so as to provide easy access thereto, as clearly illustrated in FIG. 4 of the drawings.

When the construction is fully assembled, the ring 50 fixed to the section L by the shear pins is held captive between the bottom of the socket 75 in the sleeve 70 and the lower end 44 of the upper section and so that the upper and lower sections are held against relative axial shifting, subjecting to shearing of the pins 55.

When the sleeve 70 is disengaged from the upper section U and moved downwardly, the openings 51 in the ring are exposed, providing access to the shear pins therein.

If the shear pins have been sheared or removed and for the purpose of assemblying and servicing the construction, the ring 50 can, when the sleeve 70 is disengaged from the section U and the sections U and L and shifted axially and apart from one another, be shifted axially upwardly and out of engagement about the section L, as clearly illustrated in FIG. 3 of the drawings.

In practice, a sealing ring is provided in the groove 30 to seal between the lower end of the sleeve 70 and the lower section L and a sealing ring groove 80 and sealing ring 81 is provided in the upper portion of the sleeve 70 to seal with the upper section U. With these two simple and easy to establish and maintain seals, the structure is such that fluid cannot escape from within the structure.

In practice, and in accordance with the preferred carrying out of the invention, the circumferential spacing of the shear pin receiving openings is not uniform and the longitudinal positioning of the openings in the ring is not central so that each of the openings 29 will register with predetermined openings 51 only. By intentionally providing for such a relationship of parts, obtaining or gaining proper registering or mating of openings is greatly simplified.

In practice, the number of registering pairs of openings and the resulting number of shear pins employed can be varied as desired or as circumstances require.

It is to be noted that the ring 50 is not stopped against relative rotating movement relative to the section U. Ac-

cordingly, should the drive means D allow for limited.

relative rotative movement between the sections L and U, the ring will remain fixed on the section L and will move freely circumferentially relative to the section U, with the result that the shear pins will not be acted upon, upset and/ or adversely affected by circumferential shearing forces.

It is highly important to note that the shear pins 55 are snugly engaged and maintained captive in their related openings 29 and 51 and that the shearing forces exerted onto and through the pins by each opening extend substantially a full about the pin, thereby preventing the stock of the pins from flowing and weakening before they fail under shear, as intended.

Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any modifications and/ or variations that may appear to those skilled in the art:

Having described by invention, I claim:

1. A releasing collar engageable with and between upper and lower axially aligned components of an elongate fluid conducting, axially shiftable and rotatable tubing string including, an elongate, vertically extending up per section with a central bore fixed to and communicatting with the upper component, said bore fined by the Wall of said upper section, an elongate, vertically extending lower section with a central flow passage fixed to and communicating with the lower component and telescopically engaged with and communicating with the upper section, drive means establishing rotary driving engagement between the upper and lower sections and permitting free downward movement of the lower section relative to the upper section and relasing means to releasably maintain the sections against relative axial movement and including an annular ring, means maintaining said ring in fixed axial position relative to one section, a plurality of circumferentially spaced openings in said ring and openings in the other section registering with said openings in said ring and shear pins engaged in and extending through and between the registering openings.

2. A structure as set forth in claim 1 wherein said drive means includes circumferentially spaced, radially disposed flats at the end of one section remote from its related component, and flat, circumferentially spaced, radially disposed drive surfaces on the other section slidably engaging the flats on said one section.

3. A structure as set forth in claim 1, wherein said lower section is slidably engaged in the bore in the upper section, said drive means including circumferentially spaced, radially outwardly disposed flats about the upper end of the lower section and circumferentially spaced blocks carried by the upper section and having flat, radially inwardly disposed surfaces slidably engaging the flats.

4. A structure as set forth in claim 1, wherein said lower section is slidably engaged in the bore in the upper section, said drive means positioned at and between the upper end of the lower section and the wall of the upper portion.

5. A structure as set forth in claim 2, wherein said ring is arranged about the exterior of the inner of said telescopically engaged sections and is positioned adjacent the free end of the outer of said telescopically engaged sections remote from the end of that member connected with a component, said means maintaining said ring in fixed axial position relative to the outer section including a retaining collar threaded onto said outer section to extend axially from said free end thereof to surround the ring and having an annular axially disposed shoulder spaced from and opposing said one end with said ring positioned therebetween.

6. A structure as set forth in claim 1, wherein said ring is arranged about the exterior of the inner of said telescopically engaged sections and is positioned adjacent the free end of the outer of said telescopically engaged sections remote from the end of that member connected with a component, said means maintaining said ring in fixed axial position relative to the outer section including a retaining collar threaded onto said outer section to extend axially from said free end thereof to surround the ring and having an annular axially disposed shoulder spaced from and opposing said one end with said ring positioned therebetween, said drive means including circumferentially spaced, radially outwardly disposed flats on the inner free end portion of the inner section and flat, circumferentially spaced, radially inwardly disposed drive surfaces on the outer section slidably engaging said flats.

7. A structure as set forth in claim 1, wherein said ring is arranged about the exterior of the inner of said telescopically engaged sections and is positioned adjacent the free end of the outer of said telescopically engaged sections remote from the end of that member connected with a component, said means maintaining said ring in fixed axial position relative to the outer section including a retaining collar threaded onto said outer section to extend axially from said free end thereof to surround the ring and having an annular axially disposed shoulder spaced from and opposing said one end with said ring positioned therebetween, said openings in the ring extending radially therethrough, said openings registering with the openings in the ring occurring in and extending radially through the inner section to communicate with the interior thereof, said retaining collar overlying the openings in the ring and an elongate retaining sleeve slidably engaged in the inner section to overlie the openings there in, whereby the shear pins engaged in said openings are held captive therein.

8. A structure as set forth in claim 1, wherein said ring is arranged about the exterior of the inner of said telescopically engaged sections and is positioned adjacent the free end of the outer of said telescopically engaged sections remote from the end of that member connected with a component, said means maintaining said ring in fixed axial position relative to the outer section including a retaining collar threaded onto said outer section to extend axially from said free end thereof to surround the ring and having an annular axially disposed shoulder spaced from and opposing said one end with said ring positioned therebetween, said openings in the ring extending radially therethrough, said openings registering with the openings in the ring occurring in and extending radially through the inner section to communicate with the interior thereof, said retaining collar overlying the openings in the ring and an elongate retaining sleeve slidably engaged in the inner section to overlie the openings therein, whereby the shear pins engaged in said openings are held captive therein, said drive means including circumferentially spaced, radially outwardly dis posed flats on the inner free end portion of the inner section and flat, circumferentially spaced, radially inwardly disposed drive surfaces on the outer section slidably engaging said flats.

References Cited UNITED STATES PATENTS 1,414,207 4/1922 Reed 285-2 2,924,434 2/1960 Potter et a1. 2852 X 2,937,854 5/1960 Kinley et a1. 285-3 2,988,145 6/1961 Clark 285-2 X 3,349,856 10/1967 Richardson -321 X DAVID J. WILLIAMOWSKY, Primary Examiner DAVE W. AROLA, Assistant Examiner US. Cl. X. R. 

